/Engine/Source/Runtime/Slate/Public/Framework/Docking/TabManager.h
the stack that is under NodeToSearchUnder and contains TabIdToFind; Invalid pointer if not found.
static [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FTabManager::FStack](API\Runtime\Slate\Framework\Docking\FTabManager\FStack) > FindTabUnderNode ( const FTabMatcher & Matcher, const [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [FTabManager::FLayoutNode](API\Runtime\Slate\Framework\Docking\FTabManager\FLayoutNode) > & NodeToSearchUnder )